Piping systems are commonly used to transport water, sewage, and similar fluids. When the fluid is transported under pressure, specialized pressure pipe is used which is configured to withstand the internal pressure of the fluid and the thrust forces generated by movement of the fluid through the piping system. Conventional pressure pipe is constructed using low-carbon steel cylinders that have inner and outer concrete layers and which are wound by pre-stressing steel wires, as described in U.S. Pat. Nos. 3,177,019; 3,776,576; and 5,004,274, each assigned to the Assignee of the present invention and hereby incorporated by reference in their entirety. Each of these patents further discloses restrained slip joints wherein a steel locking ring provided at one end of a first pipe section may be contracted to engage a corresponding recess provided at the end of an adjacent pipe section. This type of pipe joint has particular advantages that facilitate quick and efficient assembly of the joint restraining mechanism.
A known method of treating raw water from a source, such as a lake or reservoir, to kill viruses, bacteria, and other organic material that may be in the water, is to subject the raw water to ozone. Conventionally, ozone is bubbled through the water to be treated, or the treated water is exposed to high voltage electric discharge to create the ozone. The water may also be mixed with a solution containing a high concentration of ozone. Due to the highly unstable nature of ozone, it gradually decomposes out of the treated water, whereafter the treated water is suitable for drinking and other sanitary uses. The properties that make ozone useful for treating raw water, however, also make it highly corrosive. Accordingly, special equipment is required for the treatment and handling of ozonated water.
The treatment of water with ozone is conventionally done at a water treatment plant which services a distribution network that in turn delivers sanitized water to residential or commercial customers. Accordingly, the treatment plant must be outfitted with special equipment to ozonate the water, and holding tanks for permitting the ozone to decompose, thereby limiting the output capacity of the plant. Conventional ozonation systems have been constructed using stainless steel pipes and tanks. While stainless steel is resistant to the corrosive effects of ozone, it is quite expensive.
A need therefore exists for a cost effective treatment system which is resistant to the corrosive effects of ozone in the water and increases the throughput of treated water at the plant.